From pv magazine 07/2021
pv magazine: It’s been more than 10 years since you first published work on a 100% renewables system – what has changed since then?
Mark Jacobson, director, atmosphere/energy program, Stanford University: The first article I published was back in 2009 in Scientific American. At the time utilities didn’t think much more than 20% renewables on the grid was possible, and when we proposed to go to 100%, people laughed at us.
Since then, everything has changed. There is a lot more discussion as to how we can get to 100% renewables, and whether the costs will go up. In the U.S. we now have around 24% renewable electricity. So, we are about 8% to 9% of the way there in terms of how far we need to go to get to 100% renewables for all energy, not just electricity, in the country.
There has been this huge growth of wind and solar, and now beginning with battery storage and electric vehicles as well. In the building sector people are starting to talk about more laws being passed to ensure new buildings are energy efficient and all electric. Heavy industries and air and ship transport are also starting to electrify. There is a lot of good news, but we still need very aggressive policies to be put in place to ensure that rapid transition – at least 80% by 2030, and 100% by 2050.
I think that the biggest obstacles right now are competing interests, all of these technologies being proposed that are actually much less helpful than renewables – so carbon capture, new nuclear power, bio energy, direct air capture, geoengineering. All of these things are basically opportunity costs and distractions from real solutions.
You’ve talked about a need for increased efficiency and energy demand reduction in a 100% wind water and sunlight scenario. How do these fit with the model?
Actually just by transitioning to 100% electricity, and providing that electricity with clean renewable energy, we would reduce global power demand by around 57%. Using heat pumps instead of gas heaters, for example, reduces your energy demand for heat by 75%. Same thing with electric vehicles – in a gasoline vehicle, 20% of the energy is used to move the car, and the rest is waste heat. Whereas in an electric vehicle 80% to 85% is used to move the car.
Additionally, 12% of energy worldwide is used for the mining, transport and refining of fossil fuels and uranium – and we eliminate all of that. Electrifying industry has a smaller benefit but about a 3% to 4% reduction is possible. And then there is another 6% to 7% in energy efficiency measures beyond ‘business as usual’. That all adds up to around a 57% reduction in energy requirements just by going to 100% clean renewable energy. And if you’re using 57% less energy, the cost per unit energy being the same, you’re paying 57% less per year. We calculate that worldwide the total annual cost that people pay will be about 60% lower. So about 57% less energy use and another 10% reduction in cost per unit energy.
So the cost per unit would fall by around 10%?
That’s a conservative estimate, because wind and solar right now are half the cost of natural gas. But OK, you need backup and you have more transmission and distribution – when you account for everything, it’s a minimum 10% lower cost of energy, but you are using 57% less energy. It’s a huge reduction in cost.
How does this backup look in your models? Is it all storage?
Demand response is also a very big component, and you have transmission interconnection over large areas. On one extreme you could have 100% storage and minimal interconnection, on the other you could just interconnect the world and have no storage, because you can always get renewable power from somewhere in the world. In reality you are going to have somewhere in between, and I think storage is winning because it is just getting harder to put up new transmission lines.
There is plenty of disagreement around the price trajectories for certain materials, particularly in lithium-ion. How do you work this in?
All the trajectories I see for Li-ion, they keep coming down and it should be at $60/kWh by 2030. And for a lot of applications, you don’t need huge numbers of batteries. In my own home I have batteries, these cost 10% of the solar system, it’s just an incremental cost. And that doesn’t take me completely off the grid, but it gets me to almost 90%. And if you use heat pumps as well and reduce your energy use you need even fewer batteries.
We calculated that even if you deployed 3 TW of batteries in the United States, the overall cost of energy is still so much cheaper. I expect around $60/kWh by 2030. At those costs it is still 60% cheaper than fossil fuels to power the entire U.S. for all purposes. The batteries are only a portion of those costs, so even if batteries were 50% more expensive it would be something like 50% cheaper instead of 60%. Even at today’s prices, it’s going to be cheaper because you are using much less energy.
There is also plenty being said about shortages and environmental issues with some of the materials needed for renewables to keep growing. Do you see an issue here?
We will see periods of shortage for a lot of materials. But I don’t see limits in terms of actual resource available. Neodymium, used in permanent magnets for wind turbine generators, for example – there is seven times what you need to power the whole world with wind. For solar there are so many options that if one material is a problem there will be others available.
You might think that platinum for hydrogen fuel cells would be an issue, but actually we use platinum in catalytic convertors for ICE cars. If we don’t have these any more we have a new source of platinum, both in the existing convertors that can be recycled and in the platinum currently being used for those.
Recently you published some work on extreme weather – what did you find here in terms of renewables and resiliency?
I looked at correlation between heat demand for buildings and wind power supply. And I found remarkably strong correlation between wind power supply and heat energy demand in large, cold regions. So when it is colder and you have more demand for heat, there is also on average more energy supply from wind to meet the demand.
This correlation is strong over very large regions; Canada, Russia, Europe and the U.S. It is stronger in northern latitudes, but even as far south as Texas there is correlation between cold and wind conditions.
Your argument has long been that we already have all the technology we need to reach 100% renewables. Is there anything that is still lacking, where more research is needed?
We have 95% of the technologies that we need already commercialized and ready to go. What’s missing is long-distance aircraft or ships, but we know what we need to get there. There are also certain processes in industries like cement and steel that haven’t been commercialized, but we know how to transform steel already, for example.
The problem we’re having mostly is competition of ideas. The correct idea of electrifying everything and supplying that electricity through wind, water, solar, and storage has really hit the mainstream now. But still a lot of effort and money is being spent on appeasing the fossil fuels industry with carbon capture and related technologies.
Nuclear as well has had decades to prove itself, and it has just got more and more expensive and plants are taking longer and longer to build. Yet people still insist on spending on it. Agriculture players are pushing for biofuel crops to be used in energy, but we know that is very inefficient – photosynthesis is only 1% efficient, whereas PV is 20% efficient, so you need 20 times more land for a biofuel to give the same energy as PV. And then you have to burn the biofuel and produce pollution. It makes no sense.
Is there a danger that these could serve as distractions, slowing down the transition to renewables?
Exactly, you have special interests pushing these inefficient or polluting technologies. Carbon capture is a polluting technology because it doesn’t reduce air pollutants aside from CO2, and all the others go up because of the fact that you need more energy to run carbon capture equipment, and then you have more mining as well. There is no reason for it, except to distract us and waste money.
Until I did a study showing the impacts of carbon capture, where I looked at air pollution, mining, and social cost impacts, nobody had looked at anything except for the CO2 impact. It’s really sad that you have scientists pushing carbon capture when they don’t even bother to look at the side effects of it – how could you look at a technology and not even look at air pollution impacts or mining impacts, and just make assumptions while looking at no metrics other than CO2 change?
If you look at models that have assumed the cost of carbon capture in future scenarios, all they do is assume it reduces CO2. They don’t usually look at anything else – energy inputs or costs. And now it has been taken up by the fossil fuel industry because they have seen that spending on carbon capture can delay us getting off fossil fuels. But it will never reduce air pollution or mining, and will always incur equipment and energy costs.
So how do we move away from this?
There’s no great mystery: If we’re going to spend money innovating, lets innovate with things that are already working or that we know are 100% clean. Like offshore floating wind and solar, all sorts of solar technologies, some marine wave and tidal power. Those, as well as more storage: batteries, gravitational storage, flywheels, compressed air storage. These are things that are relevant, not small modular reactors or better ways to capture carbon out of the air. It’s just a complete waste of time and money.
Despite this, I am optimistic that we are going in the right direction. But we need to accelerate much faster. If we look at the U.S., there are now 14 states that have passed 100% renewables laws on various timeframes. And that is really awesome, this is what we need. The U.S. is still not there, although the Biden administration is doing a lot more than the previous administration to promote renewables and energy transition.
The problem right now is that the Biden administration is still appeasing the fossil fuel industry with carbon capture, and then there are nuclear and bioenergy interests – all of these special interests are unfortunately very much ingrained in policy. That is what’s slowing us down.
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